OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Twin: No Spark

Hi to all in this Victa Twin forum.

Whilst I am still a relative novice at these forums, I can tell you that the twin coils are weird creatures. In a normal single cylinder coil, one end of the HT winding is connected to the primary coil winding and BOTH are grounded to the chassis while the other end of the primary goes to the points. The other end of the HT winding goes to the spark plug and fires to earth via the plug gap.

The twin cylinder coils are relatively "stupid" in that they are a single HT winding BUT neither end is connected to the primary winding or earth and EITHER ends connect to the respective spark plugs, front and rear.

Now, to effectively test the output of these coils it is required that you ground the opposite HT lead to the side you are testing and if things are OK you should be able to throw a good blue spark for about 6 - 8mm. To test the opposite spark plug lead just ground the original HT lead and repeat the test for the other spar plug lead.

In theory, if you remove one plug lead and leave the other connected to a spark plug you should not get any spark at all ! Why? Because you effectively have an open circuit and no path to earth / chassis. In effect, the whole HT circuit in a Victa Twin coil is open circuit until the spark plugs are connected.

This is why BOTH THE SPARK PLUGS MUST BE IN EXCELLENT CONDITION AND POSE NO SUBSTANTIAL PATH TO GROUND THROUGH THEIR BODY / INSULATORS AS IF THEY DO, ONE CYLINDER WITH THE GOOD PLUG WILL GET AN EXCELLENT SPARK AND THE OTHER WILL GET BUGGER-ALL. Therefore if you change one plug for a new one it is very wise to do the other at the same time as they share what HT is available, relatively evenly, in an ideal situation. Small wonder that they cause so many problems, then. SO... the moral of this is - Always ground one of the HT lead when testing the spark AND renew the plugs as a set only.

Hope this clears up some questions for the Victa Twin fans, of which I am one. I have an original red 500T with the separate chassis mounted primer bulb and a later gold Supreme, a spare Supreme engine complete AND a spare coil. All run very well indeed.